The N20 (4-cyclinder turbo) is a great engine with enough power for most. Yes the N55 (6-cyclinder turbo) is more powerful and the differences can be felt at all RPM ranges. Selecting one vs. the other is very much (like colors) is personal decision. After some seat time if you find the need to increase the HP and torque, look at one of the aftermarket tuners. Burger now has a piggy-back tune increasing power at the wheels by 35 HP and 50 lb/ft.